Two vulnerabilities have been reported in nmbd. Alin Rad Pop (Secunia
Research) discovered a boundary checking error in the
reply_netbios_packet() function which could lead to a stack-based
buffer overflow (CVE-2007-5398). The Samba developers discovered a
boundary error when processing GETDC logon requests also leading to a
buffer overflow (CVE-2007-4572).

Impact

To exploit the first vulnerability, a remote unauthenticated attacker
could send specially crafted WINS "Name Registration" requests followed
by a WINS "Name Query" request. This might lead to execution of
arbitrary code with elevated privileges. Note that this vulnerability
is exploitable only when WINS server support is enabled in Samba. The
second vulnerability could be exploited by sending specially crafted
"GETDC" mailslot requests, but requires Samba to be configured as a
Primary or Backup Domain Controller. It is not believed the be
exploitable to execute arbitrary code.

Workaround

To work around the first vulnerability, disable WINS support in Samba
by setting " wins support = no " in the "global" section of your
smb.conf and restart Samba.